package day0901;
//作业：通过这样的格式将左边的Test5案例缩短为两行代码
public class Test6 {
    public static void main(String[] args) {
        StringBuilder  sf=new StringBuilder("好好学习java");//不安全的，效率块
        sf.append(",为了专升本").replace( 9 ,14 ,"为了改变世界").delete(0,7+1).insert(0,"活着").reverse();
        System.out.println("sf = " + sf);
    }
}